Astrodon 20 nm Filters – H-a 20nm

Astrodon 20 nm Filters – H-a 20nm

$350 – $875

4 in stock

H-a (hydrogen-alpha) at 656 nm (nanometers) is deep red in color and the most popular narrowband filter, and this 20nm H-a is the same formulation but in a wider bandpass. Hydrogen is ubiquitous in the cosmos and is present in emission nebula (North American, Pelican), planetary nebula (Dumbbell, Ring), Wolf-Rayet objects (Crescent, Thor’s Helmet) and supernova remnants (Veil). Many imagers like to present just a black-and-white H-a image of an object. It is has a beauty all by itself, like an Ansel Adams photo.